The present invention relates to an articulation for a seat and to a seat for a motor vehicle equipped with this articulation.
Already known in the state of the art is an articulation for a seat, especially for a motor vehicle, of the type comprising:
two cheeks intended to be fixed, respectively, to a seat part and to a backrest of the seat, these cheeks being able to rotate one with respect to the other about an axis of articulation which is perpendicular to them, PA1 means for coupling the cheeks together, these means being actuated by two operating members mounted so that they can rotate about the axis of articulation, movable in two opposite directions for respectively adjusting the inclination of and for folding down the backrest, between a first position in which at least one coupling member is secured respectively to the first and to the second cheek, and a second position in which this coupling member is released, and PA1 means for elastically returning the operating members to the their first position. PA1 the spring consists of a split ring, the axial edges of which are hooked into the studs; PA1 the spring plays a part in centring the rings; PA1 the articulation comprises a member for controlling the coupling means, mounted so that it can rotate about the axis of articulation, equipped with a cam interposed between the two studs, this cam being intended to interact selectively with these two studs, which form cam followers, by rotation in the directions for adjusting the inclination of the backrest and for temporarily folding this backrest down; PA1 the cam is interposed between the two studs with an angular clearance on either side of this cam; PA1 the cheeks and the rings are centred with respect to each other by complementary circular shoulders made in these elements, substantially coaxial with the axis of articulation; PA1 the cheeks are secured to a corresponding end of a coupling member by interaction of complementary shapes in particular comprising complementary toothings; PA1 the coupling member consists of a lever which can pivot about a fulcrum which, when this lever is secured to a cheek is stationary with respect to this same cheek.
In the case of a motor vehicle front seat equipped with an articulation of this type, commonly known as a memory articulation, it is possible to fold the backrest down onto the seat part in order to access the rear seats of the vehicle, and to raise this backrest up to a position of use, and to do this without altering the backrest inclination adjustment.
The object of the invention is to provide a compact and robust articulation, especially having a smaller number of components so as to avoid the appearance of undesirable play resulting from wearing of the articulation.
To this end, the subject of the invention is an articulation for a seat, especially for a motor vehicle, of the aforementioned type, characterized in that the operating members consist of two rings centred approximately on the axis of articulation and each comprising a stud formed on their interior contour, the return means comprising a spring with an angular effect hooked onto the studs in such a way as to urge the rings in opposite directions.
According to other features of the invention:
Another subject of the invention is a seat for a vehicle equipped with at least one articulation as defined hereinabove.